Digital video content is streamed to clients in real-time over traditional cable television and telephone networks, both of which are being leveraged by service providers to provide more attractive and varied services to customers. Because unique Internet Protocol (IP) addresses are a limited resource, clients that receive streamed digital video content are often located behind a NAT device. A NAT device remaps IP addresses, typically between private and public address spaces, so that multiple IP addresses in a private address space can be accessed via a single IP address that is part of the public IP address space.
The real-time streaming of digital video content from a stream server to a client often uses the User Datagram Protocol (UDP) at the Transport Layer (i.e., Layer 4) of the Open Systems Interconnection (OSI) model as defined by the International Organization for Standardization (ISO) and the Internet Engineering Task Force (IETF). Additionally, a protocol referred to as Simple Traversal of UDP through network address translators (STUN) has been developed to enable the discovery of remapped IP addresses and port numbers and also to enable traversal of inbound UDP traffic (e.g., from a stream server to a client) across a NAT device. The STUN protocol utilizes various messages to establish state information that enables UDP traffic to successfully traverse a NAT device. In addition, other control protocols such as Real Time Streaming Protocol (RTSP) are used to convey new parameters between a server and a client in order to enable real-time streaming. In video streaming applications, it may be desirable or necessary to switch the source of a video stream from one stream server to another stream server. In conventional systems, switching a video stream from one stream server to another stream server triggers a change in the state information generated from the STUN protocol and additional RTSP notifications, which can be a resource intensive operation.